题目链接: http://www.codeforces.com/contest/675/problem/E 题意: 对于第i个站,它与i+1到a[i]的站有路相连,先在求所有站点i到站点j的最短距离之和(1<=i<j<=n) 题解: 这种所有可能都算一遍就会爆的题目,有可能是可以转化为去求每个数对最后答案的贡献,用一些组合计数的方法一般就可以很快算出来. 这里用dp[i]表示第i个站点到后面的所有站的最短距离之和,明显,i+1到a[i]的站,一步就可以到,对于后面的那些点,贪心一下,一定…
E. Trains and Statistic 题目连接: http://www.codeforces.com/contest/675/problem/E Description Vasya commutes by train every day. There are n train stations in the city, and at the i-th station it's possible to buy only tickets to stations from i + 1 to a…
B. The Bakery time limit per test 2.5 seconds memory limit per test 256 megabytes input standard input output standard output Some time ago Slastyona the Sweetmaid decided to open her own bakery! She bought required ingredients and a wonder-oven whic…
 The Bakery time limit per test 2.5 seconds memory limit per test 256 megabytes input standard input output standard output Some time ago Slastyona the Sweetmaid decided to open her own bakery! She bought required ingredients and a wonder-oven which…
C. Drazil and Park 题目连接: http://codeforces.com/contest/516/problem/C Description Drazil is a monkey. He lives in a circular park. There are n trees around the park. The distance between the i-th tree and (i + 1)-st trees is di, the distance between t…
题目链接: http://codeforces.com/problemset/problem/444/C J. DZY Loves Colors time limit per test:2 secondsmemory limit per test:256 megabytes 问题描述 DZY loves colors, and he enjoys painting. On a colorful day, DZY gets a colorful ribbon, which consists of…
D. Vika and Segments 题目连接: http://www.codeforces.com/contest/610/problem/D Description Vika has an infinite sheet of squared paper. Initially all squares are white. She introduced a two-dimensional coordinate system on this sheet and drew n black hor…
题目链接:http://codeforces.com/contest/610/problem/D 就是给你宽度为1的n个线段,然你求总共有多少单位的长度. 相当于用线段树求面积并,只不过宽为1,注意y和x的最大都要+1,这样才相当于求面积. #include <iostream> #include <cstdio> #include <cstring> #include <map> #include <algorithm> using names…
题目链接:http://codeforces.com/problemset/problem/242/E 给你n个数,m个操作,操作1是查询l到r之间的和,操作2是将l到r之间的每个数xor与x. 这题是线段树成段更新,但是不能直接更新,不然只能一个数一个数更新.这样只能把每个数存到一个数组中,长度大概是20吧,然后模拟二进制的位操作.仔细一点就行了. #include <iostream> #include <cstdio> #include <cmath> #incl…
E. Kefa and Watch Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/580/problem/E Description One day Kefa the parrot was walking down the street as he was on the way home from the restaurant when he saw something glittering b…